Voltage Drop Calculator for Copper Cable
Estimate current and voltage drop for a simple single-phase copper circuit.
Formula
Planning estimate. Check product specifications and local requirements before purchasing.
Worked example: Voltage Drop Calculator
Measurements in this example
| Power | 3000 W |
|---|---|
| Voltage | 230 V |
| Cable length | 20 m |
| Cable section | 2.5 mm² |
Calculated quantities
| Current | 13.04 A |
|---|---|
| Voltage drop | 3.65 V |
What to check
This calculation uses: Power, Voltage, Cable length, Cable section. It returns: Current, Voltage drop.
Use the actual one-way cable route, conductor material and design load. Cable length in the formula includes the outgoing and return path for a simple circuit.
The answer does not select a protective device or prove cable capacity. Installation method, temperature, grouping and starting current change design limits.
Electrical work can cause fire or shock. A qualified electrician must verify conductor size, protection, earthing and local compliance.
Use the units beside each field. The values in the worked example are starting inputs; replace them with your measurements and the specifications of your material.
Compare alternatives
Open a tool, enter your measured dimensions, then save an estimate. Keep another version if you want to compare products or allowances.